a) Field of the Invention
This invention relates to a high temperature solid state hollow cylindrical rechargeable battery. More particularly, the present invention is concerned with a high temperature rechargeable lithium battery system for downhole application, such as oil and gas well logging and drilling. Still more specifically, the present invention is directed to a battery system for well logging and drilling apparatuses which can be operated even at temperatures up to 125.degree. C. and higher for extended periods of time.
b) Description of Prior Art
In oil well logging and drilling operations, primary lithium batteries such as those based on a liquid thionyl chloride electrolyte have been used to power monitoring systems to collect information such as pressure, temperature, stress, magnetic field, and the like during the drilling operation. Although these batteries have excellent energy density (typically in the range of 900 Wh/L), the task of replacing them is relatively time consuming as compared to the usable life time of the batteries. For example, a typical liquid thionyl chloride battery used in oil drilling has about 70 hours of usable operating capacity, because it is a primary cell, only about 75% of its full capacity is used to avoid facing premature battery end of life condition during a drilling mission. Furthermore, it will be noted that the operation of replacing a battery requires approximately three days.
It will be realized that from the standpoint of operation and cost, an obvious solution to the problem of having to frequently replace the battery would be to use a rechargeable battery. However, to Applicant's knowledge, high temperature rechargeable batteries for liquid or gel electrolyte systems are not presently available to achieve the above goal, unless they are provided with sufficient cooling device. Of course this is not possible nor economical in a drilling environment.
In spite of the other defects of liquid electrolyte batteries, in the context of a well logging and drilling operation, it will be obvious to one skilled in the art that, unless liquid electrolyte cells are assembled each in their own containers, it is not possible to mount them in series in a single container, which is highly desirable in well logging and drilling operations.
A review of the prior art does not seem to provide an answer to the problems outlined above. Of course, rechargeable solid polymer electrolyte batteries have been known for a number of years, and have been developed especially because they are highly rechargeable and do not have the known disadvantages of liquid electrolyte batteries. Since liquid electrolyte batteries have to be discarded after discharge in well logging and drilling operations, and because the batteries contemplated should be hollow cylindrical. U.S. Pat. Nos. 3,023,260, 4,262,064 and 4,937,154 have to be discarded as not being adaptable for the contemplated use. On the other hand, U.S. Pat. No. 5,571,632 discloses a cylindrical non aqueous electrolyte cell which is mostly characterized by the sealing means disposed at the ends of the battery. This battery does not provide an answer to the need of arranging a stack of batteries which are fixed relative to one another and operate together as a single battery container.
It is an object of the present invention to provide a solid polymer battery with a design suitable for oil and gas well logging and drilling application.
It is another object of the invention to provide a solid state battery for downhole application which can be operated even at temperatures of up to about 125.degree. C. for long periods of time.
It is another object of the present invention to provide a hollow cylindrical shaped solid polymer electrolyte battery which is made of a plurality of cells, each being laminated in a hollow cylindrical design.
It is another object of the present invention to provide a solid polymer electrolyte battery which is rechargeable and consequently can be used repeatedly in an oil well drilling environment for extended periods of time without the need to remove it from the ground.
It is another object of the present invention to provide a rechargeable solid polymer electrolyte battery that can be situated within a space provided between an inner tube and an outer tube, and to use the inner space for communication and power input wiring.
is another object of the present invention to provide a battery system wherein individual cells thereof do not require to be placed in individual containers.
It is another object of the present invention to provide a solid state battery system for downhole application that can be assembled in almost any desired shape within a drilling equipment, because of its thin solid film laminate construction.
It is another object of the present invention to provide a battery system which enables heat generated therein to dissipate through the inner and outer tubes between which the cells are mounted, while maintaining an uninterrupted operation.
It is another object of the present invention to provide a battery system wherein individual cells are interlocked to prevent their rotation relative to one another.
It is another object of the present invention to provide a battery system which incorporates removable and replaceable venting devices and especially adapted terminals.